In this article, Henrik Kniberg and Anders Ivarsson present the story of scaling Agile at Spotify with over 30 teams across 3 cities. They describe the current organization at Spotify. The Squads are similar to Scrum teams. They are self-organizing teams and some use Scrum but other use Kanban or mixed approaches.
A Tribe is a collection of squads that work in related areas. This autonomy, but the risk is a loss of economies of scale. This is why there are also groups that are Chapters and Guilds. A chapter is a small group of people with similar skills and competencies, within the same tribe. A Guild is a group of people that form a community of interest across the full organization to share knowledge, tools, code, and practices. As an example, a guild is formed by the agile coaches. The article contains a detailed description of this matrix organization.